Two novel superhard 3D sp3 hybridized carbon allotropes (Cmmm-C32 and P6/mmm-C54) are proposed in this work through first-principles calculations. Both Cmmm-C32 and P6/mmm-C54 have a honeycomb structure. P6/mmm-C54 shows a wide direct bandgap (3.564 eV), while Cmmm-C32 shows an ultrawide indirect bandgap (5.051 eV), as determined using the HSE06 hybrid functional. The hardnesses of Cmmm-C32 and P6/mmm-C54 are 83.72 and 54.01 GPa, respectively, and their calculated ideal strengths further confirm their superhardness characteristics. P6/mmm-C54 is isotropic in the (001) plane. The minimum thermal conductivities of Cmmm-C32 and P6/mmm-C54 are larger than those of diamond-C, illustrating that Cmmm-C32 and P6/mmm-C54 are potential semiconductor device materials.
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14 October 2019
Research Article|
October 14 2019
Two novel superhard carbon allotropes with honeycomb structures
Wei Zhang
;
Wei Zhang
a)
1
School of Microelectronics, Xidian University
, Xi’an 710071, People’s Republic of China
a)Authors to whom correspondence should be addressed: zw_xidian@163.com; qyfan_xidian@163.com; and fanqy@xauat.edu.cn
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Changchun Chai;
Changchun Chai
1
School of Microelectronics, Xidian University
, Xi’an 710071, People’s Republic of China
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Qingyang Fan
;
Qingyang Fan
a)
2
College of Information and Control Engineering, Xi’an University of Architecture and Technology
, Xi’an 710055, People’s Republic of China
a)Authors to whom correspondence should be addressed: zw_xidian@163.com; qyfan_xidian@163.com; and fanqy@xauat.edu.cn
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Yanxing Song;
Yanxing Song
1
School of Microelectronics, Xidian University
, Xi’an 710071, People’s Republic of China
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Yintang Yang
Yintang Yang
1
School of Microelectronics, Xidian University
, Xi’an 710071, People’s Republic of China
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a)Authors to whom correspondence should be addressed: zw_xidian@163.com; qyfan_xidian@163.com; and fanqy@xauat.edu.cn
J. Appl. Phys. 126, 145704 (2019)
Article history
Received:
July 22 2019
Accepted:
September 26 2019
Citation
Wei Zhang, Changchun Chai, Qingyang Fan, Yanxing Song, Yintang Yang; Two novel superhard carbon allotropes with honeycomb structures. J. Appl. Phys. 14 October 2019; 126 (14): 145704. https://doi.org/10.1063/1.5120376
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